1. Field of the Invention
The present invention relates to technology that outputs an image based on image data, and more specifically relates to technology that outputs an image by performing a specified image process on image data and generating dots at a suitable density.
2. Description of the Related Art
Image output devices that output images by forming dots on various types of output media such as printing media or a liquid crystal screen are widely used as output devices for various types of imaging equipment. With these image output devices, images are handled in a state finely divided into small areas called pixels, and dots are formed on these pixels. When dots are formed on pixels, of course when looking at the pixels one at a time, the only possible states are that a dot is formed or isn't formed. However, when looking at an area having a certain level of width, it is possible that looseness and denseness will occur with the density of the formed dots, and it is possible to output a multi gradation image by changing the dot formation density. For example, when forming black ink dots on printing paper, areas at which dots are formed densely look dark, and conversely, areas at which dots are formed sparsely look light. Also, when bright spot dots are formed on a liquid crystal screen, areas at which dots are formed densely look light, and conversely, areas at which dots are formed sparsely look dark. Therefore, if suitable control is done on the dot formation density, it is possible to output a multi gradation image. In this way, the data for controlling dot formation so as to obtain a suitable formation density is generated by performing specified image processing on an image to be output.
In recent years, there has been demand for higher image quality and larger images for the output images with these image output devices. For the demand for higher quality images, dividing the image into finer pixels is effective. If the pixels are made smaller, the dots formed on the pixels do not stand out, so it is possible to improve the image quality. Also, for the demand for larger images, this can be handled by increasing the pixel count. Of course, it is possible to enlarge the output image even by making each pixel bigger, but this may cause a decrease in image quality, so for the demand for larger size, it is effective to increase the pixel count.
It stands to reason that when the number of pixels that form an image is increased, image processing takes time, and outputting an image rapidly is difficult. In light of this, technology has been proposed that makes it possible to execute image processing rapidly (Unexamined Patent No. 2002-185789).
However, even if the image processing is performed rapidly, when it takes time to transfer image data or to transfer already processed image data, there are inherent limits to the acceleration effect on image output.
Also, in recent years, there is a demand of wanting to directly supply data of images taken by a digital camera or the like to an image output device such as a printing device or the like to be able to output the image immediately. In this kind of case, it is not possible to perform image processing using an image processing device equipped with high processing performance such as a so-called personal computer or the like. Therefore, it is necessary to have a simple image process for which execution is possible on either the image shooting device such as the digital camera or the image output device, or divided between both. Furthermore, even when the resolution is converted during image output, there is demand that image processing can be handled flexibly for this.